Turbine cooling



' May 10, 1949.

Filed Aug. 23, 1944 A. KALITINSKY TURBINE COOLING 2 Sheets-Sheet 1 FIG.

INVENTOR mam) ME A. KALlTlNS KY TURBI NE COOLING May 10, 1949.

2 Sheets-Sheet 2 Filed Aug. 23,- 1944 0 nmOn INVENTOR (Mm WM Patented May 10, 1949 TURBINE COOLING 7 Andrew Kalitinsky, Eagleville, Conn., assignor to United Aircraft Corporation,

East Hartford,

Conn., a corporation. of Delaware Application August 23, 1944, Serial No. 550,882

2 Claims. 1

This invention relates to cooling of gas turbines operating at high temperatures.

The copending application of Cronstedt and Ledwith, Serial No. 486,619, filed May 11, 1943, now Patent No. 2,421,833, shows a turbine in which the turbine casing is supported within a housing, the latter supporting the bearings for the opposite ends of the turbine rotor. The rotor has rows of blades alternating with rows of nozzles in the casing. An inlet duct cooperates with the casing and an exhaust duct defining a path for the power gas within and spaced from the housing. An object of the present invention is to keep the outside housing cool by radiation shields between the parts forming the gas path and the outer housing. Another feature is the circulation of a cooling fluid within the housing.

At the end of the power section the turbine may be sealed by introducing a'sealing fluid to the labyrinth 'seal at a pressure higher than that of the power gas so that this sealing fluid works toward the power section of the turbine and prevents escape of power gas into the seal. A part of the sealing fluid also works through the seal in the opposite direction. A feature of this invention is the use of this escaping fluid as the cooling fluid which is circulated within the housing.

The sealing fluid may bethe scavenge air from a free-piston unit, the exhaust gas from which is used to operate the turbine. The scavenge air is necessarily at a pressure higher than that of the exhaust power gas. Another feature of the invention is the use of the scavenge air, either directly, or after its leakage through the seal, as the coolant between the housing and the parts of the turbine forming the path for the power gas. This scavenge air having been compressed to a higher temperature than the ambient air, introduction of this air between the radiation shields adjacent tothe hot parts of the turbine Fig- 2 is a fragmentary sectional view on a larger scale of the front seal.

The turbine includes a casing Ill supported in a housing l2 by a number of radially, extending pins l4 which extend through bores in the housing and engage bores in the casing. These pins permit radial and axial expansion of the casing.

Within the casing which may have several rows of nozzle-forming vaneslB is the turbine rotor 18 having rows of blades 20 alternated with the rows of nozzles. The rotor is supported at one end by the head 22 which forms a part of the housing and at the other end by a spider 24 supported within the housing by pins 25.

Power gas enters casing l0 through aninlet duct 26 connected to the admission, end of the casing and discharges through an exhaust duct 28 which surrounds the spider 24 and has a sliding connection 30 with the discharge end of the casing. The inlet duct, the casing and the exhaust duct form a path for the power gas which is within and spaced from housing I2.

To minimize heating of the housing when the turbine is operating, radiation shields 32, 34 and 36 are placed between theparts forming the gas path and the housing and are arranged to provide a substantially uniform spacing between the shields where possible. These shields may be held in position within the housing by the same pins l 4 that hold the casing in position and also by the pins 25 that hold spider 24 in place. In addition, the spacing of the shields may be maintained by providing spaced ribs 40 integral with one or another of the shields. For ease-of asping sections which may be fitted together during assembly as, for example, shield 32 may have a I front section 42 which is applied to the main section 43 of the shield after the inlet duct is in place.

To prevent leakage of power gas around the turbine rotor adjacent the inlet end of the turbine, the rotor supports the inner elements 44 of the labyrinth seal. The outer elements 46 are carried by a sleeve 48 mounted on the head 22. Sealing air at a pressure higher than that within the power section of the turbine is admitted to the seal between its ends as by introducing the sealing gas through a passage 50, Fig. 2, in the head 22, and a passage 52 in sleeve 48. From passage 52 the air enters the seal through a port 54.

This ,sealing air works in both directions through the seal, both into the power section of the turbine and into a space 55 at the outer end of the seal. This air, which has a temperature higher than that of the surrounding atmosphere,

is directed into the space between the shields 34 and 35 by oneor more passages 56 in the-sleeve" 48. Gas entering between these shields circu- 3 lates through the path deflned by the shields and escapes at the discharge end of the turbine. The space between the shields maybe closed at the front end of the turbine by fastening the shields together adjacent the open end of the inlet duct, a connecting hood 58 extending over the ends of the shield.

The space inside of inner shield 32 and the space between shields 32 and 34 may be dead air spaces. The casing l0 and shield 32 are, as a result, not exposed directly to the cool gas and extreme temperature differential on opposite sides of the casing or the inner shields are avoided.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

Iclaim:

1. A turbine having a casing with a row of nozzles. a housing surrounding and supporting the casing, a rotor within the casing and supported by the housing, said rotor having a row of blades adjacent to, the row of nozzles and a projecting shaft, an inlet duct delivering power fluid to the nozzles, a seal around said shaft to control leakage of power fluid along said shaft, aid""means-fordischarging gas from said seal into the space between the casing and housing, said space being separate from and out of communication with the power fluid path defined within the inlet duct and the casing, said space duct defining a path for the power fluid, a rotor ,in the casing having a projecting shaft, a seal around said shaft, at least one radiation shield between the casing and housing and connected to the inlet duct, said shield defining a path for cooling fluid between the casing and housing, said cooling fluid path surrounding and independent of the path for power fluid and means for admitting fluid escaping from the turbine seal to said cooling fluid path.

- ANDREW KALITINSKY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,164,091 Herz Dec. 14, 1913 1,708,402 Schilling Apr. 9, 1929 1,828,782 Morton Oct. 27, 1931 1,960,810 Gordon May 29, 1934 2,073,605 Belluzzo Mar. 16, 1937 2,080,425

Lysholm May 18, 1937 

